Residents of 505 LaGuardia Pl. gathered Sunday to celebrate the 40th anniversary of the groundbreaking for their I.M. Pei-designed building complex and to say it would be jeopardized by an expected New York University development on the site of the Morton Williams supermarket.

They were joined by Andrew Berman, director of the Greenwich Village Society for Historic Preservation, City Councilmember Alan Gerson and former Councilmember Carol Greitzer.

G.V.S.H.P., Gerson and other local elected officials and the residents are asking the Landmarks Preservation Commission to designate the entire superblock between Bleecker and Houston Sts. and Mercer St. and LaGuardia Pl. as a landmarked district.

However, N.Y.U., which owns all of the block with the exception of some strips along the Mercer St. and LaGuardia Pl. sides, opposes the idea.

The complex includes three towers with an open lawn plaza, focused around Bust of Sylvette, a colossal Picasso sculpture.

Berman called the block endangered. We dont feel we have any time to waste, he urged.

This is not an anti-N.Y.U. campaign, Gerson stressed. We would be here if any developer were trying to do this. Gerson said he recognizes N.Y.U. needs a new science building  and more faculty housing  but the question is, he said, of the supermarket site, will it work there?

Theres no other place where you have Pei and Picasso on the same block, the Villages tallest buildings and open space, Gerson said.

Gerson added that other residents on LaGuardia Pl. and on Mercer St., in Silver Towers and Washington Sq. Village, also oppose a new development on the market site Karen Cardone, a board member of the building, said a new building would destroy the esthetics of the airy complex.

People think of its as a pinwheel plaza, she said. Everywhere you look you get a spectacular view.

About 75 percent of the 350 residents in the Mitchell Lamas 174 apartments are original tenants who are now senior citizens. One of their top fears is that they will lose the supermarket, a mainstay for the neighborhood, drawing shoppers from Soho and as far as west of Sixth Ave.

Its the only thing in the neighborhood, said Charlie Gambino. We have a lot of people in wheelchairs. This is like a retirement building.

Ive been here since 67, said Audrey Thorne, walking along slowly with a cane, as a neighbor helped her back into the building after the rally. I just hope this can be preserved.

I was the first person that moved in here, said Connie Masullo proudly. I raised four boys here. N.Y.U. gave me a luncheon when we moved in.

Tenants arent happy at the prospect of their views being blocked. They also fear being exposed to a science buildings chemical exhaust.

Im more nervous about fumes coming into the building, said Barbara Balzano, a 20-year resident, whose windows face onto Houston St.

According to a source, who requested anonymity, N.Y.U. may be eyeing its Tower Video site at Lafayette and Fourth Sts., for which it has a long-term lease with an option to buy, for its future science building, with the Morton Williams site to be used for faculty housing.

Giving a historical perspective, Greitzer recounted how in the 1960s the superblock was part of a federal urban renewal zone and was initially under the control of a private development group that was unable to proceed, after which N.Y.U. somehow ended up with the property.

According to Greitzer, then-Congressmember John Lindsay said it wasnt legal to give the block to N.Y.U., that it was supposed to go back to bid.

The city wanted to give it to N.Y.U.  but that gave a little leverage, she explained. Because of the irregularity of the process, Greitzer said, the university designated one of the Pei towers, 505 LaGuardia Pl., for the community, and it became an affordable Mitchell-Lama rental building. The other two Silver Towers are N.Y.U. housing for faculty and some graduate students.

Greitzer added that where the Coles Sports Center is today on Mercer St., N.Y.U. had promised to build a special elementary school for neighborhood children.

Dont trust N.Y.U., Greitzer warned.

She added that while N.Y.U. builds monstrous buildings, You look at the New School  they take loft buildings and redevelop them.

Gerson noted that his mentor, the late Assemblymember Bill Passannante, was involved in gaining 505 LaGuardia Pl. for the community.

He would be turning in his grave to know that this superblock would be harmed, Gerson said.

Lois Rakoff, resident co-chairperson of Bleecker Area Residents and Merchants Association, said BAMRA is going to push for the transfer from the Department of Transportation to the Parks Department of the strips on LaGuardia Pl. and Mercer St. The LaGuardia Pl. strip contains LaGuardia Corner Gardens near the supermarket. Putting the gardens under Parks jurisdiction could make it harder for N.Y.U. to extend a new building onto the plot, she said.

Noting N.Y.U. is a longtime member of G.V.S.H.P., Michael Haberman, N.Y.U. director of government and community relations, said, I think its disappointing that a group that has a long history of protecting the neighborhood is trying to landmark a supermarket.

We dont have plans for that site, Haberman said, other than what John Sexton has said, what Ive said  that we will develop that site at some point.

Haberman added that N.Y.U. has invited the Society and local elected officials to meet with the university to see what might work there  and we have gotten no responses. The Societys only response has been to misuse the landmarks law  and we find that disappointing.